I had a '92 4x4. Put a set of 31" BF Goodrich Mud Terrain's on no problem with fit. Killed the mpg and what performance there was. I had the I4 motor with intake work, full exhaust (header, pipes, bigger muffler, bigger cat...)
31's are the factory "larger" size... A lot of it will have to do with wheel offset, etc. I stuck with the stockers on my '91 4-Runner because it's such a pig. If I were to re-gear I might consider doing something else, but it's slow enough as is.